


Sleep Tight

by GlitterGluwu



Series: House Leaders Age Regressing [1]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Age Play, Anal Fingering, Anal Sex, M/M, Mommy Kink, Panic Attacks, Plot What Plot/Porn Without Plot, Psychosis, Sexual Roleplay
Language: English
Status: Completed
Published: 2020-08-16
Updated: 2020-08-16
Packaged: 2021-03-06 07:08:39
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,032
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25939429
Author URL: https://archiveofourown.org/users/GlitterGluwu/pseuds/GlitterGluwu
Summary: A whimper fluttered in Dimitri’s throat - he turned his head sharply, shifting his weight, leaning into Sylvain to lay protectively over top of him. He sobbed again.Sylvain ached for him. It was bad, tonight - he’d have to change tactics, focus more on shaping Dimitri’s unreality than on coaxing him out of it.“Mitya,” he whispered, pitching his voice a little higher on purpose this time; “Mitya, do you wanna sit on Mama’s lap?”---Sometimes, Dimitri gets deep enough into his psychoses that the best Sylvain can do is channel his thoughts in a new direction.
Relationships: Dimitri Alexandre Blaiddyd/Sylvain Jose Gautier
Series: House Leaders Age Regressing [1]
Series URL: https://archiveofourown.org/series/2072364
Comments: 7
Kudos: 82





	Sleep Tight

**Author's Note:**

> What can I say? I got a craving. (Well, that's partially true. I'm also on the "let all three house leaders age regress to cope" and the "holy shit I really haven't done a full-length Dimivain fic yet" campaign.)
> 
> I also think it's just really sexy when people call Sylvain Mommy and variations thereof. I don't know why! I just do.
> 
> It's my dream to someday do similar fics with Edelgard and Claude too, but I've got a Lot to work on and I struggle with motivation so let's check back in *checks calendar* Fifty Bazillion Years.

Sylvain awoke with a start, inhaling sharply to dispel the last lingering remnants of his dream: some unpleasantness about being snatched up and squeezed to death by a giant crawler. That sensation of being constricted, of having his lungs squeezed for every ounce of air they were willing to forfeit, didn’t seem to dissipate as quickly as the rest of it.

And then Dimitri jerked, squeezing him tighter on impulse, forcing a pained sound from Sylvain’s lips. That was it, then. Dimitri was in the midst of some night terror and Sylvain was along for the ride.

He craned his neck back before managing to peel his eyelids open, his ribs aching with the effort. Dimitri was muttering under his breath, holding Sylvain so tight to his chest that it couldn’t have been comfortable even for  _ him, _ and in seconds, Sylvain’s heart was already broken. He couldn’t yet tell if Dimitri was asleep or awake; his eye was obscured from view past the dark jut of his jaw, but even then Sylvain had encountered him sleepwalking enough times to know that might not tell him anything much.

“Do not… You shall not have him, he is not yours to take -”

Coherent sentences and a form of groundedness: that, at least, told Sylvain that he was awake, for whatever that was worth. When Dimitri was dreaming, Sylvain was seldom the ghosts’ target.

He jimmied his forearm around, his upper arm held rigid in Dimitri’s grip; he reached Dimitri’s side and patted it soothingly. “Hey, Dimitri,” he managed, his voice thin and pained even to his own ears, “Honey, you’re hurting me.”

Dimitri’s murmurs fell quiet. Sylvain could hear him swallow, but he didn’t loosen his hold. Sylvain eased his breaths in and out of his chest, staying slow, staying low - anything to prevent Dimitri from spooking further.

“Dimitri,” Sylvain rasped, and the grip lessened, just a hair - it was enough. “Thank you.”

Dimitri inhaled around a sob, just a single one. Sylvain used his newfound freedom to coax his arm further around Dimitri’s waist so that he could rub soothingly at his back. A whimper fluttered in Dimitri’s throat - he turned his head sharply, shifting his weight, leaning into Sylvain to lay protectively over top of him. He sobbed again.

Sylvain ached for him. It was bad, tonight - he’d have to change tactics, focus more on shaping Dimitri’s unreality than on coaxing him out of it.

“Mitya,” he whispered, pitching his voice a little higher on purpose this time; “Mitya, do you wanna sit on Daddy’s lap?”

Dimitri was quiet, but his breath was coming steadier. That, at least, was promising.

“Sit with Daddy?” Sylvain repeated, rubbing firmly all across Dimitri’s broad back, grounding him in his touch. “Or with Mommy?”

Dimitri swallowed again. For the first time since Sylvain’s rude awakening, Dimitri’s eye flickered toward him.

“Daddy or Mommy, baby,” Sylvain asked again. He smiled, though he didn’t quite feel it; it did seem to help Dimitri melt that little much further.

“Mama,” Dimitri mumbled, his voice sounding sticky in his throat. That single word told Sylvain two things; one, Dimitri was presenting a fair bit younger than when they usually did this. Two, this was much more likely to take a sexual turn. Understandably, Dimitri seemed less enthused about having sex with ‘Daddy’ - he’d been closer for longer with his father than with either of his mothers, after all.

“Okay,” Sylvain assented, “You have to let go for a second, okay? I have to sit up. I promise I won’t go anywhere.”

There was a flicker of hesitation, and Sylvain fretted for a moment over whether Dimitri would allow it; he glanced over his shoulder, searching the room, his eye landing on a spot where Sylvain saw nothing. “Is it a monster?” he whispered. Dimitri nodded. “It’s not gonna hurt me, I promise. I have my big, strong monster protection right here,” he added, patting Dimitri’s chest. “Right?”

Sometimes, saying things of that nature when he was regressing would make Dimitri preen - it was charming, really, when he leaned fully into the scene that way. Moments like those made it all the better for Sylvain, too. But now - now it was only enough to make him nod and pull back, allowing Sylvain to ease his way out from underneath him. He retreated backward toward the headboard, pulling a pillow closer to support his back, and sat up.

Dimitri was ready for him - the moment Sylvain was situated, Dimitri clambered mutely into his lap, laying sideways over his legs and nestling his head on his shoulder. His hands came up to his chest, folded into loose fists; one of his thumbs came to his mouth, not quite sucking, but resting on his lip for the moment. The smooth transition comforted Sylvain, too - sometimes, the trick of helping him to shift his awareness that way didn’t work quite as intended.

“Good boy,” Sylvain murmured, reaching up to brush Dimitri’s hair out of his face. He’d taken care to leave his working eye exposed, so that he could continue staring uncertainly into the space his ghost seemed to occupy; it was an improvement over the previous arrangement, but the hypervigilance wasn’t a good sign. “What can I do for you, baby?” he crooned, leaving chaste kisses on his forehead. He didn’t go for Dimitri’s mouth; he liked to let Dimitri initiate when he got like this, because he wasn’t always in the mood and it was difficult having actual  _ conversations _ about this when he was regressing.

Dimitri didn’t reply for a moment; Sylvain took the opportunity to wrap his arms around him and squeeze. One of Dimitri’s hands found his arm and squeezed gently back before he blinked, slow, and said, “Cuddle me.”

His voice was different, and that offered Sylvain a little bit more comfort. He didn’t consciously pitch his voice upward, really - it was hard to describe precisely  _ what _ was so different when he was like this - but there was a sort of stilted quality to the flow of it, a hesitation on words he wouldn’t normally hesitate on. It did smack of a younger version of Dimitri in a very real way, for Sylvain - a Dimitri he’d known who would echo his own words whenever he had the chance to teach him something new, parroting Sylvain’s diction rather than forming the words to his own tongue. It was nostalgic for Sylvain, a comfort he’d never known would be so valuable to him until the very day he first tried this.

“Okay, baby,” he breathed, tightening his arms around him, one circling his waist and the other his shoulders. He laid more kisses over his head, breathing gently, feeling Dimitri melting gradually into him as his breaths evened out. He brought his second hand up his hair, reassured by Dimitri’s calm, ruffling his long locks. “I love you so much,” he whispered.

Dimitri answered with a little hum and reopened his eye - only to startle and gasp, almost jerking right out of Sylvain’s grasp. He turned into Sylvain’s neck with a whimper and Sylvain looked up to see, only then to realize that it was another cruel projection of Dimitri’s mind.

“Oh, what is it? Is it another monster?” he asked, reaching upward and cradling his head, offering Dimitri whatever shelter he could provide. Dimitri whimpered and nodded.

“F-father,” he inhaled, and Sylvain swallowed. Part of him wondered if it was tasteless to roleplay as Dimitri’s parent when he was presently being haunted by his real father, but Dimitri always told him if he wasn’t up for the roleplay; Sylvain’s job now was to care for him until this state of mind passed.

“No, Daddy’s not here,” Sylvain spoke to him, low and slow again, as if he were a frightened horse. “Just you and me, baby. The monsters will go back where they came from, soon.”

One of Dimitri’s clinging, desperate hands found Sylvain’s sleep shirt and gripped it, threatening to tear. Sylvain kissed him again, waiting out this round of panic; he listened as Dimitri came back down, his breathing reaching a deeper place in his chest with every inhale. Sylvain kissed him one more time, smoothing his hair back from his ear, breathing deeply inward to project that he was about to speak. “Mitya, I want to make it better,” he whispered, endeared by the small, throaty sound he received in response. “Tell me what you need.”

Dimitri paused. He shifted around on Sylvain’s lap - it was another cute part about him when he was like this, how he couldn’t  _ think _ and  _ be still _ at the same time - and nuzzled further into Sylvain’s neck. “Inside,” he mumbled, and that, above all else, made Sylvain’s dick twitch. Dimitri must have felt it, because he jerked a bit, tittered a bit.

“You want me inside you?” Sylvain purred. Dimitri’s affirmative “Mhm” was almost lost in the sound of shifting bodies, of Dimitri trying to work himself around without extracting himself from Sylvain’s neck; Sylvain couldn’t help how he chuckled, charmed as ever by the simple sort of stubbornness Dimitri only ever showed in moments like these. “Baby, I need you to get off for a second,” he reasoned, and Dimitri harrumphed. “I won’t go far, I just need some wet for you, okay?”

The hesitation wasn’t all defiance, and Sylvain knew it. He felt Dimitri’s head move, as if glancing over to see whether his father was still present; Sylvain renewed his stroking of Dimitri’s hair when he subtly confirmed by turning back. “Just a couple seconds,” Sylvain promised. “I promise he won’t get me.”

Dimitri’s grasp loosened, just enough, and Sylvain took care to pull the blanket up and around him as he extracted himself, leaving Dimitri sitting upright, bundled in his comforter. He watched Sylvain - not his father - as he slid out of bed and crossed the room, finding their bottle of oil and making haste back to Dimitri. He was accepted with a grunt and open arms; Dimitri pulled him in and rubbed his cheek on Sylvain’s chest. Sylvain was stuck there at the edge of the bed for a moment as Dimitri nuzzled and sucked there, mouthing over his sleep shirt to find a nipple. He fought down a laugh.

“I know you’re relieved, but you’ve gotta let me sit down if you want inside,” he chuckled, only giggling harder as Dimitri  _ pulled, _ dragging him half-willingly forward. “No, c’mon, Mitya, you know how this works.”

Dimitri let up at last. He let Sylvain situate himself back at the head of the bed, watching hungrily - bouncing impatiently - until Sylvain beckoned to him. He shed his blanket and started tugging at his pants in the same movement, stumbling forward on his knees as he fumblingly divested himself of his sleepwear, startling another chuckle out of Sylvain’s mouth.

“There’s no rush, baby boy,” Sylvain wheezed, taking the opportunity to uncork the bottle and tip a few drops onto his fingertips. Dimitri eagerly straddled his legs, raising himself up so that his stiffening cock was commanding Sylvain’s attention, his balls hanging heavily between his legs and his hole, though not visible to him, readily available. Sylvain sucked his lips between his teeth just to see it all in the dim light of their bedroom, thighs twitching, stomach rising and falling with his breath…

_ “Mama,” _ Dimitri whined, and Sylvain tilted his head back with a warm smile. That was the best part of all - Dimitri’s face, darkened by a blush Sylvain couldn’t properly see, twisted by impatience. He had seen Dimitri pout in so many different iterations and never grown tired of the sight, but there was something delightful about the  _ shamelessness _ of it here, when he was like this.

“I’m sorry, baby,” Sylvain murmured, testing the slickness of his first two digits before reaching between Dimitri’s thighs. “I was just thinking about how cute you are.”

The very first circle of his fingertip against Dimitri’s rim had him pitching forward, planting one palm against the wall above Sylvain’s head. The next drew a gasp from him, his glutes twitching as Sylvain tested his hole with his fingertip. He was so  _ big, _ Sylvain privately thought - as much as he knew Dimitri wished otherwise, he was  _ big _ and that was  _ good, _ how he came down and laid over Sylvain like a blanket, his broad chest blocking out any sight that wasn’t Dimitri,  _ his _ Dimitri. He circled a hand around the back of Sylvain’s head and Sylvain pressed his finger gently in, hissing at the feeling of that pink, plush sort of softness within.

Dimitri was tense. It made sense, considering the torture his brain was putting him through. He took the first finger well enough, however, hiccuping with need as Sylvain felt his way in, whispering half-enunciated praises. He explored for a second, feeling Dimitri shudder - he remembered their first time together, before Dimitri had learned to find pleasure just in being filled, and smiled to himself, knowing how quickly he’d managed to change that. He teased a second finger and Dimitri begged, not with words, but with high, sweet throat sounds.

“You’re such a good boy,” Sylvain murmured unbidden, penetrating with that second finger and feeling Dimitri melt, half-sobbing. “You’re so sweet, so good.”

“Mama,” Dimitri begged, rutting forward; Sylvain felt the tip of Dimitri’s cock graze the hollow of his neck and suppressed a whine of his own. “Mama, I want inside.”

He’d give him inside. He would in a moment - but he wanted to tease him a little more first. He slipped a third finger in, feeling the clenching of Dimitri’s sphincter contrasting the willing, slick, delicious give of him further in. “Big, strong boy,” Sylvain praised him, satisfying two of his impulses at once. “You feel so good inside. I want to touch you like this all day.”

_ “No,” _ Dimitri groaned, pressing downward, bringing himself closer. “Mama,  _ inside.” _

“You’re so cute,” Sylvain teased once more, alighting with laughter when Dimitri groaned even louder. “Okay, okay. A promise is a promise.”

He withdrew his fingers, tempted to laugh again when Dimitri’s hips swayed back and forth in anticipation; it was all he could do to pull his cock from his trousers - tell Dimitri to hold back when he tried to push forward and down before he could slick himself up - and tip more oil into his palm, massaging it slowly over his length as he tilted his head back and took in his flushed, pouting baby boy.

“I’m ready, sweetheart,” Sylvain whispered, holding himself at the base as Dimitri slammed downward on instinct, fumbling to get Sylvain inside. Sylvain helped, but Dimitri did the lion’s share of the work, leaving Sylvain to hum in delight and kiss Dimitri’s cheek and purr, sated, when he finally felt that deep, hot, soft pleasure on his cock.

Dimitri didn’t waste time; he sheathed Sylvain in seconds, already crying out, bouncing impatiently - and somewhat ineffectively - for a moment before he found his rhythm. Sylvain didn’t need to do much - he held Dimitri’s hips and murmured his compliments, but Dimitri was a machine on his own. He slammed down, his voice high and clear despite the late hour, and allowed Sylvain to sit back, enjoying the visual of the firm planes of Dimitri’s body rising and falling. He let one hand wander, holding it lightly in front of Dimitri’s torso and feeling the ridges of his muscled abdomen graze the pads of his fingers as he slammed himself up and down.

“M-mam - Mama -” Dimitri choked out.

“Is it ticklish, baby?” Sylvain asked, letting his hand fall back to Dimitri’s hip. “Mama’s sorry.”

Dimitri continued riding him a few moments longer, his cock and balls bouncing with every thrust, then slowed, seeming to consider something. He tilted his head as he came to rest in Sylvain’s lap, shifting back and forth.

“What’s up?”

Dimitri pursed his lips, turning his head. He blinked. “Monster’s gone…”

“Oh? Must’ve known it wasn’t scaring you anymore,” Sylvain hummed, poking Dimitri’s belly. “Too big and strong to be scared.”

Dimitri shuffled again. He tilted his head down, seeming a little sheepish now; Sylvain wondered for a moment whether he’d come out of subspace entirely. “Rock me to sleep?” he suggested, driving that concern out of his head.

It surprised him a little, sure. It was sweet all the same. “Of course, honey,” he said, sitting up a little bit, wondering whether Dimitri would cooperate with him. He did; it didn’t take much finagling to get Dimitri onto his back with Sylvain on top of him. “Ready?”

“Mhm.”

His thrusts were shallow now, not too fast, and that seemed enough for Dimitri. He hugged Sylvain with his whole body, and Sylvain privately thought of how the whole endeavor had started - a dream about a giant crawler and Dimitri wrapped so tightly around him he couldn’t possibly escape.

He was gentler this time. He held Sylvain like something precious, and it made his heart sing.

“You want me to touch your penis?” Sylvain whispered, detecting the shorter breaths, the tighter cling. Dimitri grunted in the affirmative and Sylvain worked his hand between them, stroking him, feeling him twitching in his palm.

Dimitri came quietly, as if he were already half asleep. His limbs were heavy around Sylvain, driving him closer to his own release than even the pulsing of his hole did; he came like a whisper, the same ones he used to praise Dimitri for his performance.

“Such a good boy,” he managed, breathing into Dimitri’s neck, rubbing the planes of his shoulder and chest with firm palms. “You’re my good little boy.”

He didn’t get a response. Dimitri’s chest was rising and falling peacefully, divested of the weight of his past or the tension of his visions, and it granted Sylvain no small comfort to feel his boneless, relaxed form beneath him.

Maybe it was immature - Dimitri’s influence, or something. Sylvain found he didn’t care.

He turned his head toward where Dimitri had seen his father stand and stuck his tongue out. “Serves  _ you _ right, asshole,” he whispered, then turned back and curled up, ready to share in his love’s slumber.

**Author's Note:**

> [My Twitter](https://twitter.com/glittergluwu) | [My CuriousCat](https://curiouscat.qa/GlitterGlue) | [My Three Houses Fics](https://archiveofourown.org/users/GlitterGluwu/works?fandom_id=23985107)


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